1. Field of the Invention
The present invention relates to the manufacture of laminated doors and, more particularly, to a lock mounting insert for positioning between spaced facing sheets of a door assembly during early phases of the manufacture of a laminated door. The insert is designed so that it can accommodate door lock mechanisms of a variety of sizes and configurations.
2. Prior Art
In the manufacture of laminated doors, facing sheets formed from a variety of materials such as steel, wood, or plastics are held in closely spaced relationship. The facing sheets are often referred to as "skins." Where metal skins are used, each skin is usually provided with one or more edge flange formations extending at right angles relative to the main face of the skin. When skins of this type are assembled, the edge flange formations define opposed edges of the door. Where skins other than metal are used, rails or strips of material made from wood or plastics material are positioned about the periphery of the door to provide edge structures for the completed door.
Regardless of the material from which the skins are formed, it is desirable to fill the cavity between the spaced skins with a suitable filler material such as expanded polystyrene or polyurethane foam. The injection of this filler material into the cavity between the skins is referred to as "foaming." Once the foam solidifies or "sets," it serves to bond the skins to form a sturdy, solid, dimensionally stable door. Foam-filled doors are also desirable from the point of view of providing acoustical and thermal insulation.
In the foaming of doors, it is necessary to apply pressure to the exterior faces of the skins so that the skins will not deflect outwardly under the influence of internal pressure generated by the foam as it expands within the door cavity. If inadequate support is provided, the skins can be caused to deform and/or separate to the extent that foam is permitted to escape. If the foaming operation is carried out properly, the entire volume of the door cavity will be filled and the desired dimensional tolerances of the door will be maintained.
A problem encountered in the fabrication of foam-laminated doors is that certain areas between the skins should be left open for the eventual installation of a lock mechanism which has portions that are desirably positioned between the spaced skins. In order to facilitate the installation of locks on foamed doors, it is advantageous to form lock-receiving openings in the doors during their manufacture. Unfortunately, if openings are provided through the skins and through the door edge portions of foamed in situ door constructions, foam may escape through and/or occupy these openings during the foaming operation. This is not acceptable and the openings must be obturated in some way during foaming.
One proposal for addressing this problem has been to place an insert between the skins adjacent the preformed openings so that, during foaming, the entire volume of the door cavity except for the region of the insert is filled by the expanding foam. Where the insert performs properly, it eliminates the need for subsequent drilling, cutting and other types of foam-removal operations.
A problem with prior inserts, however, relates to their method of manufacture and their inability (1) to adapt to different door constructions, (2) to accommodate locks of different sizes and shapes, and (3) to accommodate locks having one of a selected number of a desired "set back" dimensions. Prior inserts have been made by hand from wood in a variety of configurations. These inserts have had separate components which are usually stapled together by hand. The construction of these inserts is time consuming and expensive. In fact, the speed with which these inserts can be formed often is the single most significant factor in determining the rate at which doors can be constructed. Moreover, inserts made of wood often fail to perform satisfactorily because they often are not strong enough to resist distortion under the high pressures experienced during the foaming operation. Desirably, such inserts should also provide good points of attachment for certain door lock elements; however, inserts made of wood do not adequately serve this purpose.